Clostridium difficile-associated disease (CDAD) is a hospital-acquired problem following routine antibiotic treatment. Its impact may exceed that of any other nosocomial infection. Spores of the toxin-producing pathogen are highly resistant to antibiotics and therefore overgrow the gut when broad-spectrum oral antibiotics kill off the competing bacteria. The C. difficile spores are resistant to common hospital disinfectants, thus contaminating the hospital environment and providing inoculum for infection of patients, especially the highly vulnerable elderly. Disease symptoms include diarrhea and pseudomembranous colitis. Treatment of the disease is with metronidazole or vancomycin, but relapse is commonly more than 20%. Recent spread of a more aggressive strain, that produces toxins A and B at 16 times and 23 times greater, a binary toxins, is resistant to fluoroquinolones, is hyper-productive of spores, and leads to mortality rates greater than 16%. The proposed research is to develop adjuvants for routinely used antibiotics, enabling reduction of numbers of spores in the gut and subsequently inhibiting the germination and growth of C. difficile. The treatment should prevent C. difficile overgrowth of the GI tract, allowing competing bacteria to colonize the gut and suppress the growth of C. difficile and CDAD. PUBLIC HEALTH RELEVANCE: Clostridium difficile-associated disease (CDAD) is caused by antibiotic treatment and has become the most costly and injurious hospital-acquired infection. This SBIR research proposes prevention of CDAD through the use of adjuvants with the antibiotics. [unreadable] [unreadable] [unreadable]